Copper Sulphate

The future of children's chemistry sets may be in doubt following news that there is a world shortage of copper sulphate. The compound, which has absolutely no conceivable useful properties, occurs naturally in only two places in the world - a remote river valley in southern Honduras and on a small patch of waste ground behind the post office in Harrogate. The first of these is all but mined out and the second is a protected UNESCO World Heritage site, so unless new sources can be found experts predict that supplies will run out completely by the end of 2016.

So far efforts to create copper sulphate in the laboratory have been unsuccessful, although a team in Holland have high hopes for a technique that involves firing high velocity M&Ms into a slab of granite. In the meantime, manufacturers of chemistry sets are replacing copper sulphate with other substances such as margarine, carpet fluff and earwax.

"In most cases, customers won't notice any difference," said a spokesthing. "These compounds are just as reactive as copper sulphate, with the added advantage that in at least two cases you can spread it on your toast. We don't think people will notice. After all, nobody said a word in 2007 when we substituted sprinkles for iron filings."